CA2064932A1 - Combination of heavy duty pneumatic radial tires for use in winter season - Google Patents
Combination of heavy duty pneumatic radial tires for use in winter seasonInfo
- Publication number
- CA2064932A1 CA2064932A1 CA002064932A CA2064932A CA2064932A1 CA 2064932 A1 CA2064932 A1 CA 2064932A1 CA 002064932 A CA002064932 A CA 002064932A CA 2064932 A CA2064932 A CA 2064932A CA 2064932 A1 CA2064932 A1 CA 2064932A1
- Authority
- CA
- Canada
- Prior art keywords
- tire
- circumferential
- block
- combination
- groove
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/04—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/11—Tread patterns in which the raised area of the pattern consists only of isolated elements, e.g. blocks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C5/00—Inflatable pneumatic tyres or inner tubes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
A COMBINATION OF HEAVY DUTY PNEUMATIC
RADIAL TIRES FOR USE IN WINTER SEASON
Abstract A combination of heavy duty pneumatic radial tires for use in winter season having a block pattern of a tread portion defined by plural circumferential grooves and plural lateral grooves:, each block of which pattern being provided with at least one sipe, is a tire to be mounted on a non-driven steering shaft of a vehicle and a tire to be mounted on a driving shaft thereof. In such a tire combination, a ratio of projection length of sipe to projection length of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire is not less than 0.8, and also a groove depth of the lateral groove in the tire for the non-driven steering shaft is shallower than that in the tire for the driving shaft.
RADIAL TIRES FOR USE IN WINTER SEASON
Abstract A combination of heavy duty pneumatic radial tires for use in winter season having a block pattern of a tread portion defined by plural circumferential grooves and plural lateral grooves:, each block of which pattern being provided with at least one sipe, is a tire to be mounted on a non-driven steering shaft of a vehicle and a tire to be mounted on a driving shaft thereof. In such a tire combination, a ratio of projection length of sipe to projection length of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire is not less than 0.8, and also a groove depth of the lateral groove in the tire for the non-driven steering shaft is shallower than that in the tire for the driving shaft.
Description
2~6~932 3-g6,159 A COMBINATION OF HEAVY DUTY PNEUMATIC
This invention relates to a combination of heavy duty pneumatic radial tires for use in winter season, and more particularly to a radial tire combination ef~ectively improving resistance to uneven wear while 05 highly maintaining traction performance on snow road.
For example, when a vehicle under a heavy duty is provided with a non-driven steering shaft and one or two driving shafts and two tires are mounted on the non-driven steerlng shaft and four tires are mounted on each of the driving shafts, it has been attempted to improve running performances on snow and ice road surfaces in winter season by rendering all tires into studless tires having a wider ground contacting width as far as possible. In this casel the groove depth of each of the circumferential groove and the lateral groove in the tires is generally the same irrespectively of the shaft mounting the tire.
~ ccording to such a conventional technique, however, the groove depth of the lateral groove is particularly set to a deeper depth for enhancing the traction performance of the tire on snow road, whereby the bending deformation of the block by the friction force acting on the block surface in the tire during the 2~4932 running is facilitated to en~ure the sufficient biting of the block edge into snow.
As a result, the conventional technique has a serious problem in the quality that the uneven wear is 0~ apt to be caused and particularly the violent heel and toe wear occurs in the tire mounted on the non-driven steering shaft.
It i~, therefore, an object of the invention to advantageously solve the above problems of the conventional technique and to provide a combination of heavy duty pneumatic radial tires for use in winter season capable o~ effectively improving the resistance to uneven wear while sufficiently maintaining high traction performance on snow as a whole of the vehicle.
1~ According to the invention, there is the provision of a combination of heavy duty pneumatic radial tires for use in winter season to be mounted on a : non-driven steering shaft and a driving shaft of a vehicle~ each tire comprising plural block rows located : 20 in a surface of a tread portion and separated from each othex in a widthwise direction of the tread, each of which block row being defined by plural circumferential grooves extending circumferentially of the tire and plural lateral grooves extending in a direction crossing ~with the circumferential groove, in which each block constituting each of the block rows is provided with at : -3-20~4932 least one sipe, characterized in that a projection length L~ of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire and a similar o~ projection length Ls of ~he sipe satisfy the following relation:
LS/LB '- 0.8 and a groove depth DF of the lateral groove in the tire mounted on the non-driven steering shaft is shallower 1~ than a groove depth DD of the lateral groove in the tire mounted on the driving shaft.
In a preferred embodiment of the invention, the groove depths DF and DD satisfy the following relations to a groove depth HF Of the circumferential groove in 1~ the tire mounted on the non driven steering shaft and a groove depth HD of the circumferential groove in the tire mounted on the driving shaft:
10/20 ~ DF/HF ~ 15/20 15/20 ~ DD/HD ~; 1-In such a combination of the invention, thetires to be mounted on a vehicle are classified into a tire for the non-driven stsering shaft and a tire for the driving shaft. In the tire mounted on the non-driven steerin~ shaft, the groove depth of the lateral groove is made shallower to restrain the deformation of blocks during the running of the tire, whereby the 2~932 occurrence of heel and toe wear in the tire is effectively prevented. On the other hand, the grQOVs depth of the lateral groove in the tire mounted on the driving shaft is made deeper for preventing the lowering o~ of traction performance on snow as a while of the vehicle, whereby the bending deformation of the block is facilitated through shearing force of tire treading surface from road surface to ensure sufficient biting of block edge into snow.
Therefore, in the tire combination according to the invention, the uneven wear of the tire mounted on the non-driven steering shaft can effectively be prevented, and also the lowering of the traction performance on snow in this tire can be compensated by 1~ enhanciny the traction performance on snow in the tire mounted on the driving shaft, whereby the traction performance on snow as a whole of the vehicle can be maintained at a sufficiently high level.
In the invention, the projection length LB of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire and the similar projection length s Of the sipe satisfy the relation of LSiLB 2 0.8, so that the high traction performance of the tire mounted 8~ on the driving shaft is ensured while maintaining the high braking performancs on snow in all tires.
2~6~32 When the above ratio is less than 0.8, the above performances can not sufficiently be enhanced.
In the preferable embodiment of the invention, the groove depths DF and DD of the lateral grooves are o~ restricted to satisfy the following relations to the groove depths HF and HD of the circumferential grooves in the tires to be mounted on the non-driven steering shaft and the driving shaft:
10/20 ~ DF/HF < 15/20 15/20 ~ DD/HD ~ 1 , whereby the block edges are sufficiently bitten into snow to bring about the high traction performance on snow.
When DF/HF is le~s than 10/20, the lateral grooves of the tire mounted on the non-driven steering shaft are lost before the wear.ing degree of this tire reaches S0~, whereby the running performances on snow are largely deteriorated ana as a result an official authorization as a snow tire can not be obtained.
While, when it is not less than 15/20, the rigidity of the block in the circumferential direction i~ too small and the saw-teethed uneven wear in the circumferential direction or so-called heel and toe wear becomes conspicuou~ in the tire mounted on the non-driven steering shaft.
When DD/HD is less than 15/20, the rigidity of 2~6~932 the block in the circumferential direction is too large and the biting of the block edge into snow becomes insufficient and as a result a large traction performance on snow is not obtained. Whlle, when it exceeds 1, the rubber gauge between outermost belt layer and groove bottom is too small and the appearance at last worn stage is poor and the more improvement of performances on snow can not be expected.
The invention will be described with reference to the accompanying drawing, wherein:
Fig. 1 is a diagrammatically plan view of a tread pattern used in the tire according to the invention.
In Fig. 1 is shown a plan view of the tread 1~ pattern used in the practice of the invention. This tread pattern is common in the tire mounted on the non-driven steering shaft and the tire mounted on the driving shaft.
Moreover, the internal reinforcing structure of the tire is the same as in the usual radial tire, so that it is omitted in the drawing.
The tire having a ground contacting width TW
comprises a center block row 1, a pair of shoulder block rows 2 and two pairs of block rows 3, 4 located between the center block row and the shoulder block row at its tread portion. Each of blocks la, 3al 4a in the 20~932 respective block rows 1, 3, 4 other than the shoulder block row 2 is provided with a sipe 5, 6, 7 substan-tially extending in the widthwise direction of the tread portion, while each of the blocks 2a ln the shoulder o~ block row 2 is provided with two sipes 8 substantially extending in the widthwise direction of t:he tread portion.
These block rows 1-4 are separated in the widthwise direction of the tread by a pair of circumfer-ential middle grooves 9 located at a central region ofthe tread and extending zigzag in the circumferential direction of the tire, a pair of circumferential large grooves 10 located from the middle grooves 9 toward the tread edge and extending zigzag in the circumferential 1~ direction of the tire, and a pair of circumferential fine grooves 11 located at the tread shoulder regions and extending zigzag in the circumferential direction of the tire. The blocks la-4a of the block rows 1-4 are separated in the circumferential direction of the tire by two kinds of lateral grooves 12l 13 intersecting with the circumferential grooves 9-11 and extending in the widthwise direction of the tread.
In the illustrated tire having such a tread pattern, the ground contacting width T~ i9 224 mm, the 2~ tire maximum width SW is 271 mm and the negative ratio is 33~ irrespectively of the non-driven steering shaft 2~932 and the driving shaft.
Moreover, the ratio (LS/LB) of projection length Ls Of sipe to projection length LB of block edge in each block in the widthwise direction of the tread portion o~ per unit length in the circumferential direction of the tire is 1.0 in each of the blocks la, 2a, 3a and 0.97 in the block 4a.
In these tires, according to the invention, the groove depths DF of the lateral grooves 12, 13 in the tire mounted on the non-driven steering shaft are shallower than the groove depths DD of the lateral grooves 12, 13 in the tire mounted on the driving shaft.
More preferably, the groove depths DF~ DD have the following relations to the groove depths HF, HD of the 1~ circumferential grooves 9-11 in the tires mounted on the non-driven steering shaft and the driving shaft:
10/20 ~ DF/HF < 15/20 15/20 -~ DD/HD 5 1-Thus, in the tire combination accordins to the inventionl the traction performance on snow as a whole of the vehicle i9 maintained at a sufficiently high level and particularly the uneven wear of the tire mounted on the non-driven steering shaft is effectively prevented as previously mentioned.
The following examples are given in the illustration of the invention and are not intended as :~ :
, ' .
. . ,~ . , :: ....
limitations thereof. 2 0 ~ 4 9 ~ 2 A comparative test for resistance to uneven wear and txaction performance on snow road will be described with respect to the tire combination according to the o~ invention, conventional tire combination and comparative tire combination as mentioned below.
In all tire combinations, the test tire had a tire size of 10.00R20, a tread pattern shown in Fig. 1 and a groove depth of each circumferential groove of 20 mm.
After two tires were mounted on a non-driven steering shaft of a vehicle and four tires were mounted on a driving shaft of the vehicle, they were actually run under a 100% load. After the running over a 16 distance of 20000 km, the resistance to uneven wear was evaluated by measuring a stepwise worn amount of heel and toe wear and indicating the measured amount as an index on the basis that ~he amount of 2.0 mm was 100.
On the other hand, the vehicle was run on a regulated snow road at an empty state and then a traction force thereof was measured. The traction performance was evaluated by an index on the basis that the traction force of the conventional tire combination I was 100.
The test results are shown in Table 1.
In Table 1, the larger the index value, the better the result.
2~6~932 able 1 Conven~ Conven- InYention Invention ~om~ar-tional tional tire tire a lV~
tire combina~ tlon I combi- co bi~a-tire mounted Groove on non-driven 14 16 13 11 11 depth steering of shaft lateral _ groove tire moun~ed 1416 16 16 11 _ __ __ Resistance to 100 80 110 125 125 uneven wear _ Traction pPrformance 100 120 120 120 75 on snow _ As seen from Table 1, the traction performance on snow as a whole of the vehicle and the resistance to uneven wear can simultaneously be established at a high level in the tire combination according to the invention.
As mentioned above, according to the invention, the groove depth of the lateral groove is properly selected between the tire to be mounted on the non-driven steering shaft and the tire to be mounted on the driving shaft, whereby the traction performance on snow as a whole of the vehicle is sufficiently maintained at a higher level and also the resistance to uneven wear, particularly heel and toe wear can effectively be improved.
.
.
.: .
This invention relates to a combination of heavy duty pneumatic radial tires for use in winter season, and more particularly to a radial tire combination ef~ectively improving resistance to uneven wear while 05 highly maintaining traction performance on snow road.
For example, when a vehicle under a heavy duty is provided with a non-driven steering shaft and one or two driving shafts and two tires are mounted on the non-driven steerlng shaft and four tires are mounted on each of the driving shafts, it has been attempted to improve running performances on snow and ice road surfaces in winter season by rendering all tires into studless tires having a wider ground contacting width as far as possible. In this casel the groove depth of each of the circumferential groove and the lateral groove in the tires is generally the same irrespectively of the shaft mounting the tire.
~ ccording to such a conventional technique, however, the groove depth of the lateral groove is particularly set to a deeper depth for enhancing the traction performance of the tire on snow road, whereby the bending deformation of the block by the friction force acting on the block surface in the tire during the 2~4932 running is facilitated to en~ure the sufficient biting of the block edge into snow.
As a result, the conventional technique has a serious problem in the quality that the uneven wear is 0~ apt to be caused and particularly the violent heel and toe wear occurs in the tire mounted on the non-driven steering shaft.
It i~, therefore, an object of the invention to advantageously solve the above problems of the conventional technique and to provide a combination of heavy duty pneumatic radial tires for use in winter season capable o~ effectively improving the resistance to uneven wear while sufficiently maintaining high traction performance on snow as a whole of the vehicle.
1~ According to the invention, there is the provision of a combination of heavy duty pneumatic radial tires for use in winter season to be mounted on a : non-driven steering shaft and a driving shaft of a vehicle~ each tire comprising plural block rows located : 20 in a surface of a tread portion and separated from each othex in a widthwise direction of the tread, each of which block row being defined by plural circumferential grooves extending circumferentially of the tire and plural lateral grooves extending in a direction crossing ~with the circumferential groove, in which each block constituting each of the block rows is provided with at : -3-20~4932 least one sipe, characterized in that a projection length L~ of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire and a similar o~ projection length Ls of ~he sipe satisfy the following relation:
LS/LB '- 0.8 and a groove depth DF of the lateral groove in the tire mounted on the non-driven steering shaft is shallower 1~ than a groove depth DD of the lateral groove in the tire mounted on the driving shaft.
In a preferred embodiment of the invention, the groove depths DF and DD satisfy the following relations to a groove depth HF Of the circumferential groove in 1~ the tire mounted on the non driven steering shaft and a groove depth HD of the circumferential groove in the tire mounted on the driving shaft:
10/20 ~ DF/HF ~ 15/20 15/20 ~ DD/HD ~; 1-In such a combination of the invention, thetires to be mounted on a vehicle are classified into a tire for the non-driven stsering shaft and a tire for the driving shaft. In the tire mounted on the non-driven steerin~ shaft, the groove depth of the lateral groove is made shallower to restrain the deformation of blocks during the running of the tire, whereby the 2~932 occurrence of heel and toe wear in the tire is effectively prevented. On the other hand, the grQOVs depth of the lateral groove in the tire mounted on the driving shaft is made deeper for preventing the lowering o~ of traction performance on snow as a while of the vehicle, whereby the bending deformation of the block is facilitated through shearing force of tire treading surface from road surface to ensure sufficient biting of block edge into snow.
Therefore, in the tire combination according to the invention, the uneven wear of the tire mounted on the non-driven steering shaft can effectively be prevented, and also the lowering of the traction performance on snow in this tire can be compensated by 1~ enhanciny the traction performance on snow in the tire mounted on the driving shaft, whereby the traction performance on snow as a whole of the vehicle can be maintained at a sufficiently high level.
In the invention, the projection length LB of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire and the similar projection length s Of the sipe satisfy the relation of LSiLB 2 0.8, so that the high traction performance of the tire mounted 8~ on the driving shaft is ensured while maintaining the high braking performancs on snow in all tires.
2~6~32 When the above ratio is less than 0.8, the above performances can not sufficiently be enhanced.
In the preferable embodiment of the invention, the groove depths DF and DD of the lateral grooves are o~ restricted to satisfy the following relations to the groove depths HF and HD of the circumferential grooves in the tires to be mounted on the non-driven steering shaft and the driving shaft:
10/20 ~ DF/HF < 15/20 15/20 ~ DD/HD ~ 1 , whereby the block edges are sufficiently bitten into snow to bring about the high traction performance on snow.
When DF/HF is le~s than 10/20, the lateral grooves of the tire mounted on the non-driven steering shaft are lost before the wear.ing degree of this tire reaches S0~, whereby the running performances on snow are largely deteriorated ana as a result an official authorization as a snow tire can not be obtained.
While, when it is not less than 15/20, the rigidity of the block in the circumferential direction i~ too small and the saw-teethed uneven wear in the circumferential direction or so-called heel and toe wear becomes conspicuou~ in the tire mounted on the non-driven steering shaft.
When DD/HD is less than 15/20, the rigidity of 2~6~932 the block in the circumferential direction is too large and the biting of the block edge into snow becomes insufficient and as a result a large traction performance on snow is not obtained. Whlle, when it exceeds 1, the rubber gauge between outermost belt layer and groove bottom is too small and the appearance at last worn stage is poor and the more improvement of performances on snow can not be expected.
The invention will be described with reference to the accompanying drawing, wherein:
Fig. 1 is a diagrammatically plan view of a tread pattern used in the tire according to the invention.
In Fig. 1 is shown a plan view of the tread 1~ pattern used in the practice of the invention. This tread pattern is common in the tire mounted on the non-driven steering shaft and the tire mounted on the driving shaft.
Moreover, the internal reinforcing structure of the tire is the same as in the usual radial tire, so that it is omitted in the drawing.
The tire having a ground contacting width TW
comprises a center block row 1, a pair of shoulder block rows 2 and two pairs of block rows 3, 4 located between the center block row and the shoulder block row at its tread portion. Each of blocks la, 3al 4a in the 20~932 respective block rows 1, 3, 4 other than the shoulder block row 2 is provided with a sipe 5, 6, 7 substan-tially extending in the widthwise direction of the tread portion, while each of the blocks 2a ln the shoulder o~ block row 2 is provided with two sipes 8 substantially extending in the widthwise direction of t:he tread portion.
These block rows 1-4 are separated in the widthwise direction of the tread by a pair of circumfer-ential middle grooves 9 located at a central region ofthe tread and extending zigzag in the circumferential direction of the tire, a pair of circumferential large grooves 10 located from the middle grooves 9 toward the tread edge and extending zigzag in the circumferential 1~ direction of the tire, and a pair of circumferential fine grooves 11 located at the tread shoulder regions and extending zigzag in the circumferential direction of the tire. The blocks la-4a of the block rows 1-4 are separated in the circumferential direction of the tire by two kinds of lateral grooves 12l 13 intersecting with the circumferential grooves 9-11 and extending in the widthwise direction of the tread.
In the illustrated tire having such a tread pattern, the ground contacting width T~ i9 224 mm, the 2~ tire maximum width SW is 271 mm and the negative ratio is 33~ irrespectively of the non-driven steering shaft 2~932 and the driving shaft.
Moreover, the ratio (LS/LB) of projection length Ls Of sipe to projection length LB of block edge in each block in the widthwise direction of the tread portion o~ per unit length in the circumferential direction of the tire is 1.0 in each of the blocks la, 2a, 3a and 0.97 in the block 4a.
In these tires, according to the invention, the groove depths DF of the lateral grooves 12, 13 in the tire mounted on the non-driven steering shaft are shallower than the groove depths DD of the lateral grooves 12, 13 in the tire mounted on the driving shaft.
More preferably, the groove depths DF~ DD have the following relations to the groove depths HF, HD of the 1~ circumferential grooves 9-11 in the tires mounted on the non-driven steering shaft and the driving shaft:
10/20 ~ DF/HF < 15/20 15/20 -~ DD/HD 5 1-Thus, in the tire combination accordins to the inventionl the traction performance on snow as a whole of the vehicle i9 maintained at a sufficiently high level and particularly the uneven wear of the tire mounted on the non-driven steering shaft is effectively prevented as previously mentioned.
The following examples are given in the illustration of the invention and are not intended as :~ :
, ' .
. . ,~ . , :: ....
limitations thereof. 2 0 ~ 4 9 ~ 2 A comparative test for resistance to uneven wear and txaction performance on snow road will be described with respect to the tire combination according to the o~ invention, conventional tire combination and comparative tire combination as mentioned below.
In all tire combinations, the test tire had a tire size of 10.00R20, a tread pattern shown in Fig. 1 and a groove depth of each circumferential groove of 20 mm.
After two tires were mounted on a non-driven steering shaft of a vehicle and four tires were mounted on a driving shaft of the vehicle, they were actually run under a 100% load. After the running over a 16 distance of 20000 km, the resistance to uneven wear was evaluated by measuring a stepwise worn amount of heel and toe wear and indicating the measured amount as an index on the basis that ~he amount of 2.0 mm was 100.
On the other hand, the vehicle was run on a regulated snow road at an empty state and then a traction force thereof was measured. The traction performance was evaluated by an index on the basis that the traction force of the conventional tire combination I was 100.
The test results are shown in Table 1.
In Table 1, the larger the index value, the better the result.
2~6~932 able 1 Conven~ Conven- InYention Invention ~om~ar-tional tional tire tire a lV~
tire combina~ tlon I combi- co bi~a-tire mounted Groove on non-driven 14 16 13 11 11 depth steering of shaft lateral _ groove tire moun~ed 1416 16 16 11 _ __ __ Resistance to 100 80 110 125 125 uneven wear _ Traction pPrformance 100 120 120 120 75 on snow _ As seen from Table 1, the traction performance on snow as a whole of the vehicle and the resistance to uneven wear can simultaneously be established at a high level in the tire combination according to the invention.
As mentioned above, according to the invention, the groove depth of the lateral groove is properly selected between the tire to be mounted on the non-driven steering shaft and the tire to be mounted on the driving shaft, whereby the traction performance on snow as a whole of the vehicle is sufficiently maintained at a higher level and also the resistance to uneven wear, particularly heel and toe wear can effectively be improved.
.
.
.: .
Claims (7)
1. A combination of heavy duty pneumatic radial tires for use in winter season to be mounted on a non-driven steering shaft and a driving shaft of a vehicle, each tire comprising plural block rows located in a surface of a tread portion and separated from each other in a widthwise direction of the tread, each of which block row being defined by plural circumferential grooves extending circumferentially of the tire and plural lateral grooves extending in a direction crossing with the circumferential groove, in which each block constituting each of the block rows is provided with at least one sipe, characterized in that a projection length LB of block edge in each block in the widthwise direction of the tread portion per unit length in the circumferential direction of the tire and a similar projection length Ls of the sipe satisfy the following relation:
LS/LB ? {1.8 and a groove depth DF of the lateral groove in the tire mounted on the non-driven steering shaft is shallower than a groove depth DD of the lateral groove in the tire mounted on the driving shaft.
LS/LB ? {1.8 and a groove depth DF of the lateral groove in the tire mounted on the non-driven steering shaft is shallower than a groove depth DD of the lateral groove in the tire mounted on the driving shaft.
2. The combination according to claim 1, wherein said groove depths DF and DD satisfy the following relations to a groove depth HF of the circumferential groove in the tire mounted on the non-driven steering shaft and a groove depth HD of the circumferential groove in the tire mounted on the driving shaft:
10/20 ? DF/HF < 15/20 15/20 ? DD/HD ? 1.
10/20 ? DF/HF < 15/20 15/20 ? DD/HD ? 1.
3. A combination of heavy duty pneumatic radial tires according to claim 1, wherein said blocks in one of said block rows are arranged at a given shifting amount with respect to blocks in another adjoining block row in the circumferential direction.
4. A combination of heavy duty pneumatic radial tires according to claim 1, wherein each block constituting a block row located at an outermost side of the tread is provided with two sipes extending substantially in the widthwise direction.
5. A combination of heavy duty pneumatic radial tires according to claim 1, wherein each of said tires comprises at least five block rows.
6. A combination of heavy duty pneumatic radial tires according to claim 1, wherein said plural block rows are defined by plural circumferential main grooves each extending zigzag in the circumferential direction and plural circumferential narrow grooves having width narrower than that of the circumferential main groove and extending zigzag in the circumferential direction.
7. A combination of heavy duty pneumatic radial tires according to claim 6, wherein a pair of said circumferential narrow grooves are arranged between a pair of said circumferential main grooves in a central portion of the tread and a pair of said circumferential narrow grooves are arranged outside said pair of the circumferential main grooves toward the tread ends.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3096159A JPH04306107A (en) | 1991-04-03 | 1991-04-03 | Assembly structure of heavy load radial tire for winter |
| JP3-96,159 | 1991-04-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2064932A1 true CA2064932A1 (en) | 1992-10-04 |
Family
ID=14157577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002064932A Abandoned CA2064932A1 (en) | 1991-04-03 | 1992-04-02 | Combination of heavy duty pneumatic radial tires for use in winter season |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH04306107A (en) |
| CA (1) | CA2064932A1 (en) |
| FI (1) | FI921380A (en) |
| NO (1) | NO921260L (en) |
| SE (1) | SE9201024L (en) |
-
1991
- 1991-04-03 JP JP3096159A patent/JPH04306107A/en active Pending
-
1992
- 1992-03-30 FI FI921380A patent/FI921380A/en not_active Application Discontinuation
- 1992-03-31 NO NO92921260A patent/NO921260L/en unknown
- 1992-04-02 CA CA002064932A patent/CA2064932A1/en not_active Abandoned
- 1992-04-02 SE SE9201024A patent/SE9201024L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| NO921260L (en) | 1992-10-05 |
| FI921380A (en) | 1992-10-04 |
| JPH04306107A (en) | 1992-10-28 |
| SE9201024L (en) | 1992-10-04 |
| NO921260D0 (en) | 1992-03-31 |
| FI921380A0 (en) | 1992-03-30 |
| SE9201024D0 (en) | 1992-04-02 |
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